shop made air cleaner

[Dave Schreib]

I have the opportunity to pick up a squirrel cage blower off of CL. It looks like the type they sell at the BORG where it's got a handle on top, you can move it around to dry off a wet floor, etc. Dont know what the specs on it are though.

My question to those who have used these things to make their own air cleaners: are these things more loud than the commercially available cleaners made by Jet, JDS, etc? If so, has that been a problem for you? Any succesful strategies for quieting them? Thanks in advance.

[Bob Borzelleri]

Dave, I started to comment on my home made air cleaner, but then I remembered that I have never been in a shop with a commercial unit actually running so I can't make the comparison.

While it might be a statement of the obvious, I think the most significant determinant for loudness will be the SC unit itself. Some are more quiet than others.

I built my home made unit about 10 years back. My SC is in a 3/8" (if I recall correctly), baltic birch box that is sealed with silicone. The filters include an intake screen and a 3 or 4 compartment inner cloth type bag filter. The latter is pretty heavy and I've always thought that it has to have an overall dampening effect with respect to noise.

I can certainly hear mine while it is running, but I've never found the level to be bothersome. It sure goes a long way toward "clearing the air".

[Thomas Hotchkin]

Dave, I built my SC over 10 years ago from plans in Woodsmith and has work great. My SC is in a 3/4" plywood box. The filters include an fiberglass pre-filter and a compartment inner filter. The latter is pretty heavy and I've always thought that it has to have an overall dampening effect with respect to noise. I can certainly hear mine while it is running, and have added a motor speed control to quite it down a little. But it goes a long way toward keeping the the air clean. Tom

[john clanton]

I picked up a half horse four speed motor and fan from a local hvac contractor and built an air cleaner. It is a bit noisy but it does a great job cleaning the air in the shop. Best of all it was free.

http://farm3.static.flickr.com/2702/4291458765_3e3d388099.jpg

http://farm3.static.flickr.com/2754/4292201032_08f216a6af_b.jpg

[mreza Salav]

I have the opportunity to pick up a squirrel cage blower off of CL. It looks like the type they sell at the BORG where it's got a handle on top, you can move it around to dry off a wet floor, etc. Dont know what the specs on it are though.

My question to those who have used these things to make their own air cleaners: are these things more loud than the commercially available cleaners made by Jet, JDS, etc? If so, has that been a problem for you? Any succesful strategies for quieting them? Thanks in advance.

I had a shop-vac air cleaner (those cylinder types) before I built mine. I still have both. The bigger one I built (with a furnace fan blower) is just slightly (not much) louder but it doesn't bother me as I have it running whenever I'm in the shop.
I also placed 2 layers of filters: the first one is cheaper and I clean and/or replace it more frequently than the second layer which is better/more expensive.

[Bill Blackburn]

Someone could really be a hero to us all if they'd show us the manner to wire one these these multi speed cages.
Who's the Hero gonna be?:D

[Alan Schaffter]

Someone could really be a hero to us all if they'd show us the manner to wire one these these multi speed cages.
Who's the Hero gonna be?:D

A single phase 3 speed motor should have a white common wire, a red, blue and black wire for each speed. It may also have 2 brown wires for the capacitor. You do not need a special switch for this motor you can wire it as a single speed motor using the common wire as the neutral and which ever speed you want as the hot leg. Be sure to have the two brown wires hooked to the capacitor. Or just go to the borg and buy a replacement three speed/4 position (one position is off) pull chain fan switch- that is what I did when the electronics of my Jet air cleaner fried.

Connect the incoming neutral to the neutral (white) from the motor. Then wire the hot leg to the common of the switch. Connect each speed wire from the motor to one of the poles or pigtails (depends on style of switch) on the switch this will give you a speed selector.

http://images.marketworks.com/hi/58/57750/L1689-003-EA-2.jpg

http://www.shopnutsandbolts.com/media/catalog/product/cache/1/image/182x265/9df78eab33525d08d6e5fb8d27136e95/1/0/109162_1.jpg

[Ben Bonif]

Hello to everyone here first off!

I have 3 squirrel cage fans that came from some knock-downs that we salvaged some things from before they hauled all away. I have been looking for a use for them. First thought was a downdraft sanding table and then this air filtration box but all the wires have me baffled.
I need to go and try and figure out this and maybe come back with and beg for some help if I can't get it worked out.

BTW - nice forum. I have lurked and lurked for a long time and been real hesitant to sign up as I don't feel I have much to offer but will be taxing your brains instead:o:D

[Larry Edgerton]

http://www.sawmillcreek.org/showthread.php?t=98274&highlight=squirrel+cage+filter

There is a picture of my shopmade filter made using a recycled fan from a furnace in this thread. I think the fan you are talking of is probably going to be too noisey. You do not want to have air traveling through the filter too fast and hard as it will cut its effectiveness, more particles going through the filter hather than getting trapped in the filter medium.

I used to be an off-road racer and did a lot of studying of filtration/air flow. The same principals apply here. Lots of filter area with just enough flow to draw the dust to the filter. I have seen the small filters that are sold and as far as I am concerned they are a joke, and they do not work as well as the one I built from salvage for small fraction of the cost. Their principals are all wrong, they are designed for packaging, not optimum filtration in my opinion.

[Larry Edgerton]

I picked up a half horse four speed motor and fan from a local hvac contractor and built an air cleaner. It is a bit noisy but it does a great job cleaning the air in the shop. Best of all it was free.

http://farm3.static.flickr.com/2702/4291458765_3e3d388099.jpg

http://farm3.static.flickr.com/2754/4292201032_08f216a6af_b.jpg

John

If you add more filtration by putting a filter on two or three sides it will be more effective and the fan will make less noise. You will use the same amount of filters, but you will have to change them less often. As a bonus the filters will do a better job as the air is drawn through with 1/3 of the force, hence trapping much smaller particles that would be drawn through with a single filter.

Also a heads up, if your enclosure is sealed up well as it should be, when the filters get dirty it puts a lot of strain on the fan motor. This will burn out the motor in short order, but if you listen you can hear it straining and correct.

[Alan Schaffter]

John
Also a heads up, if your enclosure is sealed up well as it should be, when the filters get dirty it puts a lot of strain on the fan motor. This will burn out the motor in short order, but if you listen you can hear it straining and correct.

This is not quite correct. It may seem contrary to reason, but these fans work like DC blowers, shopvacs and other fans- they are under maximum load and draw maximum current when wide open and unrestricted. They draw minimum current when the air is restricted and even blocked. You can verify this with an ammeter. That is one of the primary reasons DC manufacturers put small intakes on their blowers- so customers don't burn them up running them before they are connected to filters and ducting.

Though high volume/low SP furnace type fans have a totally different fan curve than high volume/moderate SP DC blowers, the effect on the motor is the same.

When you block the air flow to a shopvac the motor is no longer working hard to move air so it speeds up and therefore makes more noise. Bearing life will be reduced if you run it a long time that way, and in the case of a shopvac or other closely shrouded motor, you reduce cooling. But clogged filters don't otherwise "put a strain on the fan motor" regardless of the type of fan.

[Keith Westfall]

Workshop thread, Shop made dust filtration unit (http://www.sawmillcreek.org/showthread.php?t=132757), Feb 15, post #11 shows one that I made.

Works great and is quiet! Have walked away forgetting to turn it off if the radio is on!!

[Josh Bowman]

Dave,
I had 2 old furnace fans and because I have a stand alone shop, I mounted the fans in a 2 boxs in the attic. The ceiling became the bottom of the box, so I just cut a hole on the suction side for a 2x2 foot filter and made a slide in rack and on the discharge side I cut 3 holes for some flush mount heat and air vents. Also on the dischage I put a door on hinges that when pulled up by a cable will block off a hole on the top of the box that has a duct to the out side. That works to allow me to either recirc the air or discharge it outside. The system runs fairly quite since it's in the attic. If you want pics I can get some, it you are interested. It cleans the air well and if I goof up and have to evacuate the air in the shop :( it will do that as well.

[Alan Schaffter]

You can set your air cleaner to continue cleaning after you leave the shop. I pre-wired a switched outlet in the ceiling for my air cleaner when I built my shop, but replaced the switch with a mechanical timer from the Borg.

You can buy timers that will run from several minutes to several hours. Mine runs a max of 80 min. after I leave the shop.

http://www.ncwoodworker.net/pp/data/500/medium/IMG_2757.jpg

[Larry Edgerton]

This is not quite correct. It may seem contrary to reason, but these fans work like DC blowers, shopvacs and other fans- they are under maximum load and draw maximum current when wide open and unrestricted. They draw minimum current when the air is restricted and even blocked. You can verify this with an ammeter. That is one of the primary reasons DC manufacturers put small intakes on their blowers- so customers don't burn them up running them before they are connected to filters and ducting.

Though high volume/low SP furnace type fans have a totally different fan curve than high volume/moderate SP DC blowers, the effect on the motor is the same.

When you block the air flow to a shopvac the motor is no longer working hard to move air so it speeds up and therefore makes more noise. Bearing life will be reduced if you run it a long time that way, and in the case of a shopvac or other closely shrouded motor, you reduce cooling. But clogged filters don't otherwise "put a strain on the fan motor" regardless of the type of fan.

I"m not saying you are wrong, you may be right but... I have had this system for about fifteen years and on both occasions that I had to replace the fan motor it was after being in too big of a hurry to climb up and change the filters. It may well be under less load, but it certianly has less cooling air, and it will fail if the filters are clogged. Further I am not sure I agree as the sound coming from the motor is definately the sound of a motor laboring hard. I didn't check it with a load meter, but when the filters are plugged the speed of the fan is audibly slowed, and if left long enough it will start to make nasty noises. As soon as you put in new filters, the nasty squealing noises go away.

[John M Bailey]

I"m not saying you are wrong, you may be right but... I have had this system for about fifteen years and on both occasions that I had to replace the fan motor it was after being in too big of a hurry to climb up and change the filters. It may well be under less load, but it certianly has less cooling air, and it will fail if the filters are clogged. Further I am not sure I agree as the sound coming from the motor is definately the sound of a motor laboring hard. I didn't check it with a load meter, but when the filters are plugged the speed of the fan is audibly slowed, and if left long enough it will start to make nasty noises. As soon as you put in new filters, the nasty squealing noises go away.


The reason the nasty squealing noises go away when you put new filters on your dust collector is that the motor turns much faster than the bushing are designed for when the filters are clogged and little or no air is going through.
A fan motor will burn out without the load of air, not because it is laboring too hard, but because it is turning too fast.
Check it with a load meter. No air, very little load. But, the bearings are hot and burning.

[Larry Edgerton]

The reason the nasty squealing noises go away when you put new filters on your dust collector is that the motor turns much faster than the bushing are designed for when the filters are clogged and little or no air is going through.
A fan motor will burn out without the load of air, not because it is laboring too hard, but because it is turning too fast.
Check it with a load meter. No air, very little load. But, the bearings are hot and burning.

I'll just take you guys word for it. I just assumed......:)

[David Hostetler]

FWIW, I am in the collecting the stuff phase of a similar project. (Have to get my truck and my tail to Galveston to pick up the blower). Once I have working blower and motor in hand, I will get with the measuring. I am wanting to build a copy of the Shop Notes "Complete Small Shop" air cleaner. A cheap lower grade pleated filter, a fine ultra allergen filter in a row on the intake side, then another ultra allergen filter on the output side of things.

I need to figure the wiring for it out, but I figure a mechanical timer, to a 3 speed switch (3 speed motor thankfully!) and then to the motor... I figure I will have a problem getting to the timer though.

[Todd Hyman]

You can set your air cleaner to continue cleaning after you leave the shop. I pre-wired a switched outlet in the ceiling for my air cleaner when I built my shop, but replaced the switch with a mechanical timer from the Borg.

You can buy timers that will run from several minutes to several hours. Mine runs a max of 80 min. after I leave the shop.

http://www.ncwoodworker.net/pp/data/500/medium/IMG_2757.jpg

I did something similar to Alan but I used a 3-switch switch (Broan bathroom exhaust fan switch from Lowes) that fits into a single gang box along with a 12 hour timer and wired them in series the 3-switch is set up for 3 different speeds and works great.